Many various types of valves useful for the said purpose are known in the art, for instance disk valves, cone valves, and rotatable ball valves having a flow passageway in the valve ball. All such valves are disadvantageous for use in valves subjected to high liquid pressures. The pressure from the liquid may make it difficult to open the valve, since the opening must be made by a movement the direction of which is opposed to the liquid pressure; it may be difficult to close the valve in a calm course, since the liquid, depending on the pressure thereof against the valve disk or valve cone, tends to provided a quick and violent closing movement; in many cases the liquid pressure against the valve cone or against the rotatable valve ball may create a high friction which must overcome; in some cases the high liquid pressure may tend to provide an unintentional partly opening of the valve; the quick movement of liquid under high pressure also may provide cavitation damages both on the valve cone and on the valve seat. Further, many known valves are so bulky that they are not suited for use in snow making machines.